Okay, coming back to the anemometer by the use of the components of an old ball-based mouse, it will be possible to adapt this idea to measure the RPM of the anemometer, following the idea and sketch proposed in this instructable:

I have a very old mouse recovered from the garbage bin without some component, so i am not so worry about to kill the mouse. But i agree with you that is better to do your own. Thanks for the link, i think that i will go through it to develop my anemometer.Thanks!

The anemometer in my 1-wire weather station has a reed switch and a magnet. The roughest part to solve is having a GOOD bearing on the spinning element that will stand up to the elements year in year out.

It looks like I count 2 pulses per revolution... I'm not sure you need something more complicated. A mouse interrupter would provide way more sensitivity than you need if you want to count revolutions that translate to Miles per Hour wind speed.

Many of these were made at the time. I even heard of one being calibrated in the wind tunnel of British Aerospace. Several hundred were made and I got lots of good feedback. It was very low cost and used just on opto slot detector. I even sold on to a person in Greenland!I don't sell the bits any more but it uses the system of brass tubes and rods you get in model shops.

Please, don´t understand bad. Your project with the anemometer (as well as others of your projects that i saw in this forum) are great and provide a huge background and useful experience for the novices such as myself.

When i said coming back to the anemometer... "by the use of a ball mouse", i was coming back to talk about the use of this components started in previous posts. I was not trying to say that your anemometer was bad or not useful. I am sure that your system is really proffesional meanwhile this one that i have on my by the use of an old ball mouse is a simple, not accurate, and for sure not so valid. But i have not experience on electronics, so this is an starting point to learn about sensors an electronics.

So, please, don´t believe that i was trying to discard your device, just only providing other information and other ideas. If what i wrote sound bad to you, i am sorry, but it was not my intention. May be it could be cause because my very bad english (it is not my native language).

So, thanks for your comments and ideas in this an other posts. Please follow sharing your experience with us.